Fast response thermochromatographic capillary columns

Abstract

A thermochromatographic column has a fused silica capillary with a high temperature chemically inert polymer coating thereon supporting a thin heater film formed by the deposition of either a high resistance metallic compound auto-catalytically from a solution of the compound or a nichrome film sputtered onto the polymer clad capillary tubing. The electrical contacts to the heater film may be either resistance welded thereto or the electrically conductive wires may be attached to the capillary body and integrated into the heater film during the deposition of the heater film. An outer layer of an electrically insulating material is applied to the heater film to electrically isolate the heater film and to protect the heater film from damage.

The embodiments of the present invention in which an exclusive property or privilege is claimed are defined as follows: 
     
       1. A chromatographic column comprising capillary means having an outer surface and heater means including a resistive material in the form of a uniform homogeneous film deposited as a continuous enveloping layer completely covering said outer surface of said capillary means wherein said resistive film includes a sputtered film of nichrome deposited on said surface of said capillary means. 
     
     
       2. A chromatographic column as set forth in claim 1 wherein said resistive film includes electrical terminal means connected to respective ends of said resistive film. 
     
     
       3. A chromatographic column as set forth in claim 2 wherein said terminal means include electrically conductive bands encircling and in contact with said respective ends of said resistive film. 
     
     
       4. A chromatographic column as set forth in claim 1 wherein said capillary means includes a fused silica tube having an outer layer of a high temperature chemically inert polymer forming said outer surface. 
     
     
       5. A chromatographic column as set forth in claim 4 wherein said heater means includes an outer layer of a high temperature, chemically inert polymer on said resistive film. 
     
     
       6. A chromatographic column comprising capillary means having an outer surface and heater means including a resistive material in the form of a uniform homogeneous film deposited as a continuous enveloping layer completely covering said outer surface of said capillary means wherein said resistive film includes a nickel phosphide layer deposited on said outside surface of said capillary. 
     
     
       7. A chromatographic column as set in claim 6 wherein said resistive film includes electrical terminal means connected to respective ends of said heater means. 
     
     
       8. A chromatographic column as set forth in claim 7 wherein said terminal means include electrically conductive bands encircling and in contact with respective ends of said resistive film. 
     
     
       9. A chromatographic column as set forth in claim 6 wherein said capillary means includes a fused silica tube having an outer layer of a high temperature, chemically inert polymer forming said outer surface. 
     
     
       10. A chromatographic column comprising capillary means having an outer surface and heater means including a resistive material in the form of a uniform homogeneous film deposited as a continuous enveloping layer completely covering said outer surface of said capillary means wherein said capillary means includes a fused silica tube having an outer layer of a high temperature chemically inert polymer forming said surface and wherein said heater means includes an outer layer of a high temperature, chemically inert polymer on said resistive film and wherein said resistive film includes a nickel phosphide layer deposited on said outer layer on said capillary means. 
     
     
       11. A chromatographic column as set forth in claim 10 wherein said heater means includes electrical terminal means connected to respective ends of said resistive film. 
     
     
       12. A chromatographic column comprising capillary means having an outer surface and heater means including a resistive material in the form of a uniform homogeneous film deposited as a continuous enveloping layer completely covering said outer surface of said capillary means wherein said capillary means includes a fused silica tube having an outer layer of a high temperature chemically inert polymer forming said outer surface and wherein said heater means includes an outer layer of a high temperature, chemically inert polymer on said resistive film and wherein said resistive film includes a sputtered film of nichrome deposited on said outer layer on said capillary means. 
     
     
       13. A chromatographic column as set forth in claim 12 wherein said resistive film includes electrical terminal means connected to respective ends of said heater means.